Bit-brace chuck.



H. P. RICHARDS.

BIT BEACH CHUCK.

APPLICATION FILED IEB.7, 1910,

Patented June 7, 1910.

PHOTOLITM OGRAPHERS. wAsmNm ANDREW B. GRAMM UNITED srerrns PATENT ornion.

HUBERT P. RICHARDS, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TO THE STANLEY RULE & LEVEL COMPANY, OF NEW BRITAIN, CONNECTICUT, A CORPORATION OF CONNECTICUT.

To all whom it may concern:

Be it known that I, HUBERT P. RICHARDS, a citizen of the United States, residing at New Britain, county of Hartford, State of Connecticut, have invented certain new and useful Improvements in Bit-Brace Chucks, of which the following is a full, clear, and exact description.

My invention relates to chucks of that class particularly adapted for use in connection with a so-called bit brace, the object of the present invention being to provide an improved construction to control the jaw movement.

This invention is essentially an improvement upon the construction set forth in my former United States Letters Patent No. 817,936, dated April 17, 1906.

In the accompanying drawings Figure 1 illustrates the lower part of a bit brace provided witha chuck of my improved construction, said view. being partly broken away; Fig. 2 is acentral longitudinal sectional view of the chuck showing the jaws fully open to take a round drill shank of large size; Fig. 3 is a similar view showing the jaws partially contracted, and as they would appear when holding a round drill shank of smaller size; Fig. 4 is a view similar to Fig. 3 and showing the aws in the position assumed when holding a tapered angular shank such as provided on the ordinary boring bit; Figs. 5, 6 and 7 are detail Views.

In the particular form of my invention shown herein, 1 represents what I will term the driver or driving element. In this instance, the driver is adapted to be manually driven by an ordinary bit brace, a portion of the bow of which is indicated at 2. The driver includes an elongated round body having a longitudinal jaw-receiving slot in its lower end, the outer surface beingscrewthreaded to receive a corresponding screwthread formed upon the inside of the jaw operating member or shell 3. This screwthreaded connection is indicated at 4. 5 is a stationary or fixed abutment block arranged in the bottom of said recess and having its forward end cut back or recessed to provide the two inclines 5 5 forming a fixed sloping abutment. The side surface of said block is provided with a longitudinally arranged groove or slot 5 terminating preferably near the forward end of said block at a point close to and between the inclines Specification of Letters Patent.

Application filed February '7, 1910.

Patented June '7, 1910.

Serial No. 542,517.

5 5-. 55 are clearance recesses at each side of said groove 5 the function of which will later be explained.

6-6 are jaws arranged in the slotted part of the driver. The forward or outer end of the shell 3 is tapered inwardly, as shown at 3 to provide a sloping abutment arranged to coact with the tapered outer ends of the jaws 66 77 are toggle links pivotally connected together at 8, one end of said pivot provid .ing a laterally projecting stud 8 as best seen in Fig. 5. The free ends of the links 77 are provided with lateral pin like bearings 99 arranged respectively for pivotal connection with the tail ends of the jaws 66 The extreme tail end of each jaw is preferably beveled off to take a proper bearing against the fixed abutment inclines 5 5 at the front of block 5.

10 is a spring suitably connected with the jaws 66 at points intermediate of their ends, said spring operating to move said jaws apart. I

When the parts are assembled, as shown in the drawings, the bearing end of stud 8 stands in, and may partake of longitudinal movement in the groove 5 in the block 5. The toggles 7-7 move freely in the clearance recesses 55, while the pin-like bearings 99 pivotally engage the tails of the jaws 66*. 7

Operation: Assuming the parts stand in the position indicated in Fig. 2, if a drill with a round shank of uniform diameter is inserted between the jaws 66 and the shell 3 is manually turned in a direction to carry it back on the driver 1, the movable abutment 3 will engage the forward tapered ends of both jaws 6 and move the jaws back upon the inclines 55 of the fixed abutment block 5, said inclines cooperating to move said jaws toward each other in substantial parallelism, the pin 8 sliding freely rearwardly in the groove 5 in the abutment block. This continues until the jaws firmly grip the round shank of the drill. The function of the toggle links 7-7 is two-fold; they prevent the independent longitudinal displacement of the jaws 6-6 and also cause the jaws to move to and fro in parallel planes. When the drill is to be released the shell 3 is rotated in a direction to move it outwardly upon the driver 1, whereupon. the action of the spring 10 (by reason of the locality of its connection with the jaws) opcrates to open said 'aws in substantial parallelism, the rear en 5 moving apart upon the inclines 5 5 to the same degree as the forward ends move apart upon the tapered abutment incline at the forward inner end of the shell3. If it is desired to grip a tapered angular tool shank, for example as illustrated in Fig. 4:, the drawing back of the shell 3 or the driver will tend toclamp the jaws 66- down upon said tapered shank, said jaws then shifting out of parallelism and adapting themselves to the incline of said tapered shank. During this operation the toggle connections operate'to cause the jaws to assume like positions of angularity relatively to a common center line through the chuck as well as parallel positions for round shank tools, all of which results not only in a most effective gripping of the tool itself, but also in causing said tool to line up correctly relatively to thecenter line of the chuck. V

By reason of the simplicity of the construction and the fewness of parts, there is comparatively no friction tending to impede the free action of the jaws.

What I claim is: r

1. In a chuck, in combination, a driver, a pair of jaws, two oppositely faced slo ing abutments, one of which is movable, oth abutments engaging the opposite ends of said jaws to move them toward each other when said abutments approach each other, a pair of toggle links hinged to each other at one end and pivoted to the jaws at their free ends, a laterally projecting bearing stud at the hinged end of said toggles and a guide'slot in the side of one-of said abutments for said bearing stud, said guide slot I being coincident with the axis'of said chuck.

2. In a chuck, in combination, adriver, a pair of jaws, two oppositely faced sloping abutments, one of which is 1 movable, both abutments engaging the opposite ends of said jaWs to move them toward each otherj when said abutments approach each other, a pair of toggle links hinged to each other at one end and pivoted to the jaws at their 3. In a chuck, in combination, a driver, a

pair of jaws, two oppositely faced sloping abutments,v one of which'is movable, both abutments engaging the opposite ends of said jaws to move them toward each other when said abutments approach each other, a pair of toggle links hinged to each other at one end and pivoted to the jaws at their free ends, a laterally projecting bearing stud at the hinged end of said toggles and a guide slot in the side of one of said abutments for said bearing stud,'said guide slot being coincident with the axis of said chuck, and a clearance recess in said abutment block at each sideof said guide slot,'-said toggles abutments engaging the opposite ends of said jaws to move them toward eachother when said abutments approach each'other,'

a pair of togglelinks hinged to each other atone end and pivoted to the jaws at their free ends, 'a laterally projecting bearing stud at the hinged end of said-toggles and a guide slot in the side of oneof said abutmentsfor HUBERT P. RICHARDS.

VVitnesse's: I a

W. J. WORAM, H. S. WOLTER. 

